1. Field of the Invention
The present invention relates to a video playback system and an image display device.
2. Description of the Related Art
Functions that transmit a video to a projector via a network and have the projector project the video are known, such as projecting a personal computer screen for transmitting a screen image of a personal computer to a projector via a network for having the projector project the screen image, and a projector complying with a standard called Miracast for transmitting a video via a wireless local area network (LAN).
Common projectors operate with limited resources (such as a central processing unit (CPU) and a memory), and processing such as projection of a video thus overloads such projectors. With these functions, a video is adjusted to a projectable size on the personal computer side before transmitted to the projector, so that the projector does not need to perform resizing or other processing. Thus, load on the projector is reduced.
A digital zooming function is installed to a projector. With this function, the size of a screen is decreased through image processing, and the projector is thus not necessarily placed at a distance when projecting an image. The digital zooming function is settable by a user at any timing. The projector therefore needs to perform reduction processing on the projected image at any timing.
When reduction processing is additionally ordered to a projector spending maximum performance for playing a video or performing another function in parallel, the projector may fail to provide enough performance. In the case of performing the reduction processing on the personal computer side instead of on the projector side, the personal computer may also fail to provide enough performance if another function is simultaneously performed in the personal computer side or the personal computer already has a large workload.
When the performance is degraded as a result of image processing required through a user operation on the projector side or other jobs ordered on the personal computer side or the projector side during playback of a video transmitted through a network, as a solution to the problem, such a method is considered for securing the performance that causes a device with smaller load to perform image processing.
Japanese Laid-open Patent Publication No. 2010-061542 describes a communication terminal that displays a content on the display unit in accordance with the specification information of the communication terminal.
When a video playback condition is changed while the video is played, a time lag is problematically caused before the changed playback condition is reflected. For example, in the case of performing reduction processing on the personal computer side for digital zooming, a time lag is caused between operation of digital zooming and projection of the data having undergone the reduction processing.
Therefore, there is a need to provide a video playback system and an image display device that, when a playback condition of a video is changed while the video is played, reduces a time lag caused before the changed playback condition is reflected.